Magnum Energy MM-AE Series - Manual (Page 30)

©
2010 Magnum Energy, Inc.
3.0 Operation
24
Standby Mode
The MM-AE Series features an automatic transfer relay and an internal
battery charger when operating in the Standby Mode. The Standby
Mode begins whenever AC power (utility or generator) is connected
to the inverter’s AC input. Once the AC voltage and frequency of the
incoming AC power is within the AC input limits, an automatic AC
transfer relay is activated. This transfer relay passes the incoming AC
power through the inverter to power the AC loads on the inverter’s
output. This incoming power is also used to activate a powerful in-
ternal battery charger to keep the battery bank charged in case of
a power failure.
Battery charging
- The MM-AE Series models are equipped with an
active Power Factor Corrected (PFC) multi-stage battery charger. The
PFC feature is used to control the amount of power used to charge
the batteries in order to obtain a power factor as close as possible to
1 (or unity). This causes the battery charger to look like a resistor to
the line (forces the charge current waveshape to mirror the voltage
waveshape). This feature maximizes the real power available from
the AC power source (utility or generator), which translates into less
power wasted and a greater charging capability than most chargers
available today.
When an AC source (utility power or generator) is connected to an
inverter that has a battery charger, the inverter monitors the AC
input for acceptable voltage. Once the inverter has accepted the AC
input, the AC transfer relay will close and charging will begin. Once
charging, the DC voltage is monitored to determine the charging
stage. If the DC voltage is low (≤12.9 VDC/12 volt models or ≤25.8
VDC/24 volt models), the charger begins bulk charging. If the DC
voltage is high (>12.9 VDC/12 volt models or >25.8 VDC/24 volt
models), the charger skips the initial Bulk/Absorb Charging stages
and goes directly to fl oat charging.
The multi-stage charger can use up to fi ve different charging stages
to help monitor and keep the batteries healthy. The fi ve stages
include an automatic 4-stage charging process (Bulk, Absorb, Float,
and Full Charge), and a manual Equalization (EQ) charge stage. The
automatic 4-stage charge process provides complete recharging and
monitoring of the batteries without damage due to overcharging (see
Figure 12). The Equalization stage (requires the ME-RC50 remote)
is used to stir up stratifi ed electrolyte and reverse any battery plate
sulfation that might have occurred .
While charging, the unit may go into Charger Back-off protection
which automatically reduces the charge current to the batteries.
This is caused by:
1. The internal temperature is too hot – the charger automatically
reduces the charge rate to maintain temperature; or,